1. Field of the Invention
This invention generally concerns gaming tokens such as disks, flat plaques, or cards, which integrate an electronic chip or an electronic identification device. The applications for the present invention are to be found, amongst others, in the contactless identification or electronic labeling of persons and objects, and in the authentication, identification tracking and counting of gaming tokens, also called casino chips. The expression “gaming token” covers any token that can be used in a gaming room and representing a value that is predetermined or not. Gaming tokens are usually molded from a rigid plastic material to obtain a structure that is solid enough to resist conditions of use in casinos. The plastic token may include edge spots defined by plastic pieces of various colors embedded around the periphery. The term “token” is used herein to refer to any flat body that may include an electronic circuit.
2. Discussion of Background Information
U.S. Pat. No. 6,021,949, commonly owned with the present application, the entire disclosure of which is hereby expressly incorporated by reference, describes a gaming token or plaque, the body of which integrates an electronic chip made from laminated sheets of rolled plastic material. The electronic chip or electronic identifier includes an electronic circuit with a memory bearing identification and/or coding information concerning the person or object associated with the token (electronic label) or the token itself (gaming token or payment token). The electronic circuit is generally associated with an emitter-receiver connected to an antenna and adapted to be supplied by inductive coupling. The electronic chip is placed in the center of an opening provided in the body of the token, protected and held on either side by two rigid wafers and finally joined together and integrated into the body of the plaque by a lamination of top sheets of transparent cellulose acetate followed by the thermoforming of the assembly.
The manufacturing process for the body of the plaque incorporating the electronic chip by laminating thin sheets of plastic material described in the above mentioned patent was well adapted to highly decorated plaques and those representing a high nominal value, usually manufactured in small or medium sized series. However, protection of the electronic chip when integrated into the body of the plaque required a certain thickness, usually between 4 and 6 mm. Gaming tokens or plaques with a thickness of about 3 mm and equipped with an electronic chip were difficult to manufacture using this method, with an excessive number of rejects resulting from the destruction of the chip.
To facilitate the manufacture of thinner game tokens, commonly assigned U.S. Pat. No. 6,581,747, the entire disclosure of which is hereby expressly incorporated by reference, discloses a gaming token made of plastic with a cavity in which an electronic identification device is placed. The electronic device includes an emitter-receiver and a peripheral antenna placed between two thin plastic films joined along their peripheries to form a protective envelope or pellet. The cavity offers at least one face opening closed by a plastic plug inserted into the cavity and assembled directly with the flat body, retaining the electronic device therein.
This structural arrangement made the token very robust while reducing its thickness by eliminating any superfluous layer of plastic. The deformation capacity of the plug ensured a very robust weld, and a good cohesion between the token body and the thus completed electronic identifier.
However, the electronic device utilized in the above-mentioned prior art, was small, incorporating components capable of operating with only a relatively low frequency. To accommodate higher frequencies, a larger diameter, electronic pellet was necessary. The increased size was found to be accompanied by an increased incidence of breakage of the pellet envelope. Because the electronic pellet was heterogonous rather than homogeneous, stresses from the deforming plastic plug were concentrated at certain points of the envelope, causing the plastic film to break. Also, there was no direct interconnection between the upper and lower surfaces of the token, weakening the structure. Thus, the manufacturing process was accompanied by a high number of rejected defective tokens.
To lessen the damage and the number of defects, a token was developed which provided a recess in the body of the token to accommodate the circuitry of the electronic identifier and through holes were placed in the pellet envelope. The through holes allowed plastic to flow through and interlock the top and bottom of the token, while the recess accommodated the different thicknesses of the electronic identifier components. This inventive effort is the subject of commonly assigned U.S. Provisional application 60/686,419, filed Jun. 2, 2005.
Although the tokens of the prior art produced robust tokens and addressed the concerns of damage to the electronic identifier, the edge spots, in tokens so equipped, were found to be deformed and diffused by excess plastic material flowing across the surface of the token in the final molding press operation. The final molding required a relatively high level of compression, which also subjected the electronic identifier to an increased chance of being damaged.